Process of preparing amine sulfonates and products obtained thereof



Patented Nov. 3, 1953 TENT OFFICE PROCESS OF PREPARING AMINESULFO- NATES AND PRODUCTS OBTAINED THEREOF Milton Kosmin, Dayton, Ohio, assignor to Mon- -santo Chemical Company, St. Louis, Mo., acorporation of-Delaware No Drawing. Application May 17, 1951,

Serial No. 226,948

g 7 Claims.

' 1 The present 'invention'relates tomethods of preparing taurine derivatives and provides an improved method for the'manufacture of higher N alkyltaurines and valuable surface-active agents comprising certain new taurine derivatives.

An object of the invention is the provision of acommercially feasible method for the preparation of salts of N-alkyltaurines in which the alkyl radical hasfrom 8lto 18carbon atoms. Another object of the invention is to preparecompounds possessing very good surface-active properties from readily available raw materials. Still another object of the invention is to provide compounds which simultaneously possess superior detersive, Wetting-out :and lathering properties.

These and other objects hereinafter disclosed are provided by the following invention wherein an isethionic acid compound selected from the class consisting of isethionic acid-and Z-methylisethionic acid and the alkali metal, alkaline earth metal, and ammonium'salts of such acid is heated with an-alkylamine of'from 8 to 18carbon atoms to yield N-alkyltaurines or the corresponding salts thereof in which the alkyl radical has from 8 18 carbon atoms, substantially according to the scheme:

in which'R is..an-alkyl radical of from 8 .to .18 carbon atomsfR' is. selected. from the class consisting of hydrogen and the methyl radical and X is selected from the class consisting of hydrogen, alkali metal, alkaline vearth metal and aim monium.

Alkylamines suitable for the present purpose are,.for example noctylamine, (2-ethyl-hexyl)- amine, n decylamine, tert-dodecylamine, -(2- butyloctyDamine, n-undecylamine, n-tetradecylamine, (7-ethyl-2-methyl) undecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylaim ine, etc. Isethionic .acid compounds which may be condensed with the alkylamines for the preparation of the present N-alkyltaurines are, e. g., isethionic acid or Z m'ethyliSethiOnic acid, sodium isethionate, sodium 2-methylisethionate, potassium isethionate, lithium isethionate; magnesium 2-.methylisethionate, calcium isethionate, barium 2-methylisethionate, ammonium isethionate, etc. The isethionates'or the Z-methylisethionates are readily availableby the reaction of an alkali metal ,or alkaline earth metalhisulfite with ethylene oxide :or propylene-oxide.

froeessespreviously employedfor the preparation of higher N-alkyltaurines have been inexpedient for commercial operation because they either required the use of diflicultly available starting materials or because yields of the desired materials, based on the quantity of amino compound used, Were very low due to theformation of large quantities of by,-products. 'Thus in the German Patent 551257 issued to Ottet al.,there is described the production of the sodium salt of N-heptadecyltaurine by condensation of heptadecylamine with sodium 2-c,hloroethanesulfonate. In this process, apart of the heptadecylamine is neutralized by he h drog chloride erol ed in the condensation; hence'the process is of little commercial value in'that not onlyis a considerable excess of initial amine requiredbutgalso there result operating, diifi cu1ties ini'fiheseparation by by-product heptadecylamine hydrochloride from the N-heptadecyltaurine.

In prior art, e. g., aspin.the.Nicodemus.U. S. Patent No. 1,932,907, N-alkylamines in which, the alkyl radical has, from .lto 4 carbonatomsihave been condensed with isethiom'c. acid ornsalts thereof in aqueous solution and .undersupfllatmospheric pressure to ,y eld theeorresponding lower N-alkyltaurines, i. e.,.taurines in which the alkyl radical has from 1 to .4 carbon atoms. Now I have found that in. spiteof. the fact thatsuperatmospheric pressure-was employed when work?- ing with the comparatively more reactive lower alkylamines, condensation of the usuallyzmore sluggish higher alkylamines with isethiom'c acid or salts thereotmaybe readilyeffected-11ml?! ordinary conditionsof pressure.

In preparing the higher N-alkyltaurines or salts thereof by the present process, I operate substantially as iollows: I, heat a mixtureoi an alkylamine of from 8 to lllpcarbonatoms and the isethionic or ZFmeth-ylisethi ni c.ompo und th ereof to temperatures: oi fro n, -say, C. to 300C. until the ma ion of th -hi e N-allirltarrine compound. Advantageously, Lemploy no ter or-other diluent, although anhydrous-cond tions nee-:1 not be observed.v Since; the eactionoecurs by condensationoflone ole of thealkyla Withone mole of the"hydroxyalliulsulfcnate,requimolar proportions of the reactants generally may be employed. In practice, it may be preferable to use a slight-excesstof -.w hichevercomponent is more readily obtainableorder to assuregcomplete reaction of the lessreadily obtainable eactant. The reactionprogluet, i, e.,i ;he,h;1gl;1 er ky a ri s mp und; is: sep rated from: the reaction mixture by simply-removin any.;11n :e acted constituent, e. a,zby; distilline,z-;decantingfor ing properties.

3 extracting, and drying the product. Generally, the use of substantially equimolar proportions of the alkylamine and the isethionic compound and heating at temperatures of over 180 C. for a time of, say, from one hour to a day, assures complete reaction of both components so that the reaction product consists of the substantially pure, waxy or crystalline higher N-alkylamine compound. In this case no further treatment of the product is required.

Higher N-alkyltaurines prepared by the present process are white, waxy to crystalline solids. The alkali metal and ammonium salts are generally water-soluble and, like most long-chained sulfonates, the individual members of this series are generaliy characterized by possessing varying degrees of surface-activity. While some members of the series are distinguished by good wetting properties, very good detersive properties or outstanding lathering ability, generally a single member of the series does not possess all three of these desirable characteristics, e. g., outstanding detersive properties is present in a compound having poor lathering properties, or the good wetting-out property of a single member is not accompanied by adequate detersive and/or lather- I have found, however, that salts of N-tetradecyltaurine, and particularly the alkali metal and ammonium salts thereof, are unique in that they are characterized by possessing a combination of outstanding detersive, wetting-out, and lathering properties. The provision of a single compound possessing such general superiority constitutes a notable advancement in the art.

The invention is illustrated, but not limited, by the following examples.

Example 1 A mixture consisting of 50 g. (0.338 mole) of sodium isethionate and 80 g. (0.362 mole) of N-tetradecylamine was heated rapidly to a temperature of 20 C. and maintained for 5 minutes at this temperature. The temperature of the reaction mixture was then slowly raised to 245 C. and maintained at about this temperature, with stirring, for about 2 hours. After allowin the resulting reaction mixture to cool it was extracted with 250 ml. of ethanol in order to remove excess amine. Upon drying there was obtained 95.1 g. (80.5% theoretical yield) of the sodium salt of N-tetradecyltaurine. As shown in Example 6 it was found to possess out-standing detersive, wetting-out and lathering properties.

Example 2 50 g. (0.388 mole) of sodium isethionate was mixed with '75 g. (0.565 mole) of N-octylamine in an atmosphere of nitrogen at a temperature of about 150 C. and the resulting mixture was maintained, with stirring, at about the melting point of the sodium isethionate (about 181 C.) for several hours. Unreacted amine was then removed from the cooled product by extracting with ethanol. The dried residue comprised the substantially pure sodium salt of N-octyltaurine.

Example 3 50 g. (0.388 mole) of sodium isethionate was mixed with 65 g. (0.350 mole) of N-dodecylamine in an atmosphere of nitrogen at a temperature of from 225-230 C. for- 3 hours and then at a temperature of 250 C. for 1.5 hours. The white, waxy, solid obtained upon cooling the reaction mixture in an atmosphere of nitrogen comprised the crude sodium salt of N-dodecyltaurine. Removal of unreacted dodecylamine from the crude product was effected by heating it with absolute ethanol and separating the resulting ethanol solution of unreacted amine. The residue comprised the substantially pure sodium salt of N-dodecyltaurine which was found to show very good detersive properties.

Example 4 In this example there is employed an alkylamine prepared from the mixture of alcohols obtained by hydrogenation of coconut-oil fatty acids, which amine will be hereinafter referred to as cocoamine. '70 g. (0.340 mole) of the amine was mixed with 50 g. (0.338 mole) of sodium isethionate in a nitrogen atmosphere, the mixture was heated rapidly to a temperature of 205 C. kept at this temperature for 30 minutes and then slowly raised to 225 C. The mixture was then maintained, with stirring, at a temperature of from 220-250 C. for a time of about 2 hours. In the course of the heating 4.3 g. of the amine distilled over with the water of the reaction. Ihe distilled amine, together with 10 more grams of cocoamine, was returned to the reaction mixture. After cooling the reaction mixture to room temperature in an atmosphere of nitrogen it was removed from the reaction vessel and the unreacted amine was extracted with slightly alkaline ethanol. There was thus obtained 89.5 g. of dried residue comprising the substantially pure sodium salt of N-alkyltaurine in which the alkyl radical is derived from coconut oil fatty acids.

Example 5 85.0 g. (0.316 mole) of octadecylamine and 44.5 (0.30 mole) of sodium isethionate were mixed and heated in an atmosphere of nitrogen at 225230 C. for 4.5 hours and then at 245 C. for 1.5 hours. After cooling, the reaction product was dissolved in aqueous alcohol. Separation and drying of the aqueous layer gave the sodium salt of N-octadecyltaurine, a substantially waterinsoluble compound which showed no surface ac tivity.

Example 6 the American Society for Testing Materials. The following results were obtained.

Detergency, percent of Gardinol:

% active In 50 p. p. m. water hardness In 300 p. p. In. water hardness 100 Built In 50 p. p. m. water hardness 114 In 300 p. p. m. water hardness 106 1 40% of the sodium salt of N-tetradec ltaur' 60% of builder consisting of 96.2% sodium gilfatef ffi g giggthylene glycol, and 1.75% of anhydrous sodium phos- Speed of wetting in seconds (Draves) At 0.5% concentration 18.8 At 0.25% concentration 18.3 At 0.125% concentration 33.0

At 0.0625% concentration 129.0 Ross-Miles lather heights (cm): In 50 p. p. no. water hardness- At once 12.9

After 5 min 12.9 In 300 p. p. in. water hardness- At once 16.1

After 5 min. 16.0

What I claim is:

1. The process of producing N-alkyltaurines having the formula RNHC(R)H.CH2SO3X in which R is an alkyl radical of from 8 to 18 carbon atoms, R is selected from the class consisting of hydrogen and the methyl radical and X is selected from the class consisting of hydrogen, alkali metal, alkaline earth metal and ammonium which comprises heating, at atmospheric pressure and at a temperature of 180 C.300 C., an alkylamine of from 8 to 18 carbon atoms with a compound selected from the class consisting of isethionic acid and 2-methylisethionic acid and the alkali metal, alkaline earth metal and ammonium salts of said acids.

2. The process of producing alkali metal salts of N-alkyltaurine in which the alkyl radical has from 8 to 18 carbon atoms which comprises heating, at atmospheric pressure and at a temperature of 180 C.-300 C., an alkali metal isethionate with an alkylamine of from 8 to 18 carbon atoms.

3. The process of preparing the sodium salt of N-tetradecyltaurine which comprises heating tetradecylamine With sodium isethionate at atmospheric pressure and at a temperature of 180 C.300 C.

4. The process of preparing the sodium salt of N-octyltaurine which comprises heating octylamine with sodium isethionate at atmospheric pressure and at a temperature of from 180 C. 300 C.

5. The process of preparing the sodium salt of N-dodecyltaurine which comprises heating dodecylamine at atmospheric pressure and at a temperature of from 180 C.-300 C.

6. The process of preparing the sodium salt of an N-alkyltaurine in which the alkyl radical is derived by hydrogenation of coconut oil fatty acids which comprises heating, at atmospheric pressure and at a temperature of C.-300 C., sodium isethionate with an alkylamine in which the alkyl radical is derived by hydrogenation of coconut oil fatty acids.

'7. The process of preparing the sodium salt of N-octadecyltaurine which comprises heating octadecylamine with sodium isethionate at a temperature of from 180 C.300 C. and at at mospheric pressure.

MILTON KOSMIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,944,300 Ott et a1 Jan. 23, 1934 1,999,614 Nicodemus et al. Apr. 30, 1935 

1. THE PROCESS OF PRODUCING N-ALKYLTAURINES HAVING THE FORMULA RNHC(R'')H.CH2SO3X IN WHICH R IS AN ALKYL RADICAL OF FROM 8 TO 18 CARBON ATOMS, RH IS SELECTED FROM THE CLASS CONSISTING OF HYDROGEN AND THE METHYL RADICAL AND X IS SELECTED FROM THE CLASS CONSISTING OF HYDROGEN, ALKALI METAL, ALKALINE EARTH METAL AND AMMONIUM WHICH COMPRISES HEATING, AT ATMOSPHERIC PRESSURE AND AT A TEMPERATURE OF 180* C.-300* C., AN ALKYLAMINE OF FROM 8 TO 18 CARBON ATOMS WITH A COMPOUND SELECTED FROM THE CLASS CONSISTING OF ISETHIONIC ACID AND 2-METHYLISETHIONIC ACID AND THE ALKALI METAL, ALKALINE EARTH METAL AND AMMONIUM SALTS OF SAID ACIDS. 